packet-cgmp.c

   1 /* packet-cgmp.c
   2  * Routines for the disassembly of the Cisco Group Management Protocol
   3  *
   4  * $Id: packet-cgmp.c,v 1.7 2001/01/03 06:55:27 guy Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@zing.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  24  */
  25
  26 #include "config.h"
  27
  28 #ifdef HAVE_SYS_TYPES_H
  29 #include <sys/types.h>
  30 #endif
  31
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include <glib.h>
  36 #include "packet.h"
  37
  38 /*
  39  * See
  40  *
  41  * http://www.barnett.sk/software/bbooks/cisco_multicasting_routing/chap04.html
  42  *
  43  * for some information on CGMP.
  44  */
  45
  46 static int proto_cgmp = -1;
  47 static int hf_cgmp_version = -1;
  48 static int hf_cgmp_type = -1;
  49 static int hf_cgmp_count = -1;
  50 static int hf_cgmp_gda = -1;
  51 static int hf_cgmp_usa = -1;
  52
  53 static gint ett_cgmp = -1;
  54
  55 static const value_string type_vals[] = {
  56         { 0, "Join" },
  57         { 1, "Leave" },
  58         { 0, NULL },
  59 };
  60
  61 static void
  62 dissect_cgmp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  63 {
  64         proto_item *ti;
  65         proto_tree *cgmp_tree = NULL;
  66         int offset = 0;
  67         guint8 count;
  68
  69         CHECK_DISPLAY_AS_DATA(proto_cgmp, tvb, pinfo, tree);
  70
  71         pinfo->current_proto = "CGMP";
  72
  73         if (check_col(pinfo->fd, COL_PROTOCOL))
  74                 col_set_str(pinfo->fd, COL_PROTOCOL, "CGMP");
  75         if (check_col(pinfo->fd, COL_INFO))
  76                 col_set_str(pinfo->fd, COL_INFO, "Cisco Group Management Protocol");
  77
  78         if (tree) {
  79                 ti = proto_tree_add_item(tree, proto_cgmp, tvb, offset,
  80                     tvb_length_remaining(tvb, offset), FALSE);
  81                 cgmp_tree = proto_item_add_subtree(ti, ett_cgmp);
  82
  83                 proto_tree_add_item(cgmp_tree, hf_cgmp_version, tvb, offset, 1,
  84                     FALSE);
  85                 proto_tree_add_item(cgmp_tree, hf_cgmp_type, tvb, offset, 1,
  86                     FALSE);
  87                 offset += 1;
  88
  89                 offset += 2;    /* skip reserved field */
  90
  91                 count = tvb_get_guint8(tvb, offset);
  92                 proto_tree_add_uint(cgmp_tree, hf_cgmp_count, tvb, offset, 1,
  93                     count);
  94                 offset += 1;
  95
  96                 while (count != 0) {
  97                         proto_tree_add_item(cgmp_tree, hf_cgmp_gda, tvb, offset, 6,
  98                             FALSE);
  99                         offset += 6;
 100
 101                         proto_tree_add_item(cgmp_tree, hf_cgmp_usa, tvb, offset, 6,
 102                             FALSE);
 103                         offset += 6;
 104
 105                         count--;
 106                 }
 107         }
 108 }
 109
 110 void
 111 proto_register_cgmp(void)
 112 {
 113         static hf_register_info hf[] = {
 114                 { &hf_cgmp_version,
 115                 { "Version",    "cgmp.version", FT_UINT8, BASE_DEC, NULL, 0xF0,
 116                         "" }},
 117
 118                 { &hf_cgmp_type,
 119                 { "Type",       "cgmp.type",    FT_UINT8, BASE_DEC, VALS(type_vals), 0x0F,
 120                         "" }},
 121
 122                 { &hf_cgmp_count,
 123                 { "Count",      "cgmp.count", FT_UINT8, BASE_DEC, NULL, 0x0,
 124                         "" }},
 125
 126                 { &hf_cgmp_gda,
 127                 { "Group Destination Address",  "cgmp.gda", FT_ETHER, BASE_NONE, NULL, 0x0,
 128                         "Group Destination Address" }},
 129
 130                 { &hf_cgmp_usa,
 131                 { "Unicast Source Address",     "cgmp.usa", FT_ETHER, BASE_NONE, NULL, 0x0,
 132                         "Unicast Source Address" }},
 133         };
 134         static gint *ett[] = {
 135                 &ett_cgmp,
 136         };
 137
 138         proto_cgmp = proto_register_protocol("Cisco Group Management Protocol",
 139             "CGMP", "cgmp");
 140         proto_register_field_array(proto_cgmp, hf, array_length(hf));
 141         proto_register_subtree_array(ett, array_length(ett));
 142 }
 143
 144 void
 145 proto_reg_handoff_cgmp(void)
 146 {
 147         dissector_add("llc.cisco_pid", 0x2001, dissect_cgmp);
 148 }